<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>参与者模式测试</title>
</head>
<body>
    <button> 未设置参与对象</button>
    <button> 设置参与对象 </button>
    <button> 设置参与对象为p </button>
    <p></p>

    <script src="./07-participator-4.js"></script>
</body>
</html>